Today there is available a number of known devices for presentation of a caller's telephone number via CTI system signalling (Computer Telephony Integration), e.g, via DTMF (Dual-Tone Multiple Frequency), V.23 or the like to an individual subscriber connection. Private persons today have the possibility to store the latest received calls including time information together with phone numbers obtained from the number presentation for a caller, even if only in a limited extent. Thus, it is possible to later call a person who did call earlier, as the phone number of the person will be known by means of the number presentation for the caller. However there is no possibility for a company to utilize such on the market available caller number presentation devices as available devices only can read one line. Consequently, a totally different system to collect the caller's phone number for presentation of all the lines is needed for a company to be able to bring such information together from several phone lines.
Existing presentation of caller's number in Sweden include calls from private persons, calls from mobile phones within the NMT systems NMT-450 and NMT-900 and from mobile phones of the GSM distributors Telia and Europolitan. The presentation of a caller's phone number does not include restricted phone numbers, i.e. subscribers having a secret phone number, and also still no calls from the GSM distributor ComViq, but the phone numbers of this distributor will most probably in a short time be available. A subscriber's phone number concerning an international call is however not yet presented, but the Swedish telephone distributor Telia do have plans to introduce presentation of caller's number also for calls from abroad.
Presentation of caller's number from technical reasons does not include telephone subscriptions not connected to a suitable exchange system, but these systems are continuously expanded and today there are few subscribers who are not connected to such a type of exchange not offering this facility.
There is therefore a demand for a system which will present numbers from a multiplicity of lines simultaneously, whereby, for instance, a company then should be able, e.g. to make statistics over received calls and divide the incoming calls to the company such that a certain client always basically can get the same contact person guided by the subscriber number of the call. Such a system should also preferably store a subscriber number calling the company after closing hours, when nobody is available at the company and can answer the telephone.